"""
Form Widget classes specific to the Django admin site.
"""

import copy

from django import forms
from django.forms.widgets import RadioFieldRenderer
from django.forms.util import flatatt
from django.utils.text import truncate_words
from django.utils.translation import ugettext as _
from django.utils.safestring import mark_safe
from django.utils.encoding import force_unicode
from django.conf import settings

class FilteredSelectMultiple(forms.SelectMultiple):
    """
    A SelectMultiple with a JavaScript filter interface.

    Note that the resulting JavaScript assumes that the SelectFilter2.js
    library and its dependencies have been loaded in the HTML page.
    """
    def __init__(self, verbose_name, is_stacked, attrs=None, choices=()):
        self.verbose_name = verbose_name
        self.is_stacked = is_stacked
        super(FilteredSelectMultiple, self).__init__(attrs, choices)

    def render(self, name, value, attrs=None, choices=()):
        output = [super(FilteredSelectMultiple, self).render(name, value, attrs, choices)]
        output.append(u'<script type="text/javascript">addEvent(window, "load", function(e) {')
        # TODO: "id_" is hard-coded here. This should instead use the correct
        # API to determine the ID dynamically.
        output.append(u'SelectFilter.init("id_%s", "%s", %s, "%s"); });</script>\n' % \
            (name, self.verbose_name.replace('"', '\\"'), int(self.is_stacked), settings.ADMIN_MEDIA_PREFIX))
        return mark_safe(u''.join(output))

class AdminDateWidget(forms.TextInput):
    class Media:
        js = (settings.ADMIN_MEDIA_PREFIX + "js/calendar.js", 
              settings.ADMIN_MEDIA_PREFIX + "js/admin/DateTimeShortcuts.js")
        
    def __init__(self, attrs={}):
        super(AdminDateWidget, self).__init__(attrs={'class': 'vDateField', 'size': '10'})

class AdminTimeWidget(forms.TextInput):
    class Media:
        js = (settings.ADMIN_MEDIA_PREFIX + "js/calendar.js", 
              settings.ADMIN_MEDIA_PREFIX + "js/admin/DateTimeShortcuts.js")

    def __init__(self, attrs={}):
        super(AdminTimeWidget, self).__init__(attrs={'class': 'vTimeField', 'size': '8'})
    
class AdminSplitDateTime(forms.SplitDateTimeWidget):
    """
    A SplitDateTime Widget that has some admin-specific styling.
    """
    def __init__(self, attrs=None):
        widgets = [AdminDateWidget, AdminTimeWidget]
        # Note that we're calling MultiWidget, not SplitDateTimeWidget, because
        # we want to define widgets.
        forms.MultiWidget.__init__(self, widgets, attrs)

    def format_output(self, rendered_widgets):
        return mark_safe(u'<p class="datetime">%s %s<br />%s %s</p>' % \
            (_('Date:'), rendered_widgets[0], _('Time:'), rendered_widgets[1]))

class AdminRadioFieldRenderer(RadioFieldRenderer):
    def render(self):
        """Outputs a <ul> for this set of radio fields."""
        return mark_safe(u'<ul%s>\n%s\n</ul>' % (
            flatatt(self.attrs),
            u'\n'.join([u'<li>%s</li>' % force_unicode(w) for w in self]))
        )

class AdminRadioSelect(forms.RadioSelect):
    renderer = AdminRadioFieldRenderer

class AdminFileWidget(forms.FileInput):
    """
    A FileField Widget that shows its current value if it has one.
    """
    def __init__(self, attrs={}):
        super(AdminFileWidget, self).__init__(attrs)
        
    def render(self, name, value, attrs=None):
        output = []
        if value:
            output.append('%s <a target="_blank" href="%s%s">%s</a> <br />%s ' % \
                (_('Currently:'), settings.MEDIA_URL, value, value, _('Change:')))
        output.append(super(AdminFileWidget, self).render(name, value, attrs))
        return mark_safe(u''.join(output))

class ForeignKeyRawIdWidget(forms.TextInput):
    """
    A Widget for displaying ForeignKeys in the "raw_id" interface rather than
    in a <select> box.
    """
    def __init__(self, rel, attrs=None):
        self.rel = rel
        super(ForeignKeyRawIdWidget, self).__init__(attrs)

    def render(self, name, value, attrs=None):
        related_url = '../../../%s/%s/' % (self.rel.to._meta.app_label, self.rel.to._meta.object_name.lower())
        if self.rel.limit_choices_to:
            url = '?' + '&amp;'.join(['%s=%s' % (k, v) for k, v in self.rel.limit_choices_to.items()])
        else:
            url = ''
        if not attrs.has_key('class'):
          attrs['class'] = 'vForeignKeyRawIdAdminField' # The JavaScript looks for this hook.
        output = [super(ForeignKeyRawIdWidget, self).render(name, value, attrs)]
        # TODO: "id_" is hard-coded here. This should instead use the correct
        # API to determine the ID dynamically.
        output.append('<a href="%s%s" class="related-lookup" id="lookup_id_%s" onclick="return showRelatedObjectLookupPopup(this);"> ' % \
            (related_url, url, name))
        output.append('<img src="%simg/admin/selector-search.gif" width="16" height="16" alt="Lookup" /></a>' % settings.ADMIN_MEDIA_PREFIX)
        if value:
            output.append(self.label_for_value(value))
        return mark_safe(u''.join(output))
    
    def label_for_value(self, value):
        return '&nbsp;<strong>%s</strong>' % \
            truncate_words(self.rel.to.objects.get(pk=value), 14)
            
class ManyToManyRawIdWidget(ForeignKeyRawIdWidget):
    """
    A Widget for displaying ManyToMany ids in the "raw_id" interface rather than
    in a <select multiple> box.
    """
    def __init__(self, rel, attrs=None):
        super(ManyToManyRawIdWidget, self).__init__(rel, attrs)
    
    def render(self, name, value, attrs=None):
        attrs['class'] = 'vManyToManyRawIdAdminField'
        if value:
            value = ','.join([str(v) for v in value])
        else:
            value = ''
        return super(ManyToManyRawIdWidget, self).render(name, value, attrs)
    
    def label_for_value(self, value):
        return ''

    def value_from_datadict(self, data, files, name):
        value = data.get(name, None)
        if value and ',' in value:
            return data[name].split(',')
        if value:
            return [value]
        return None
    
    def _has_changed(self, initial, data):
        if initial is None:
            initial = []
        if data is None:
            data = []
        if len(initial) != len(data):
            return True
        for pk1, pk2 in zip(initial, data):
            if force_unicode(pk1) != force_unicode(pk2):
                return True
        return False

class RelatedFieldWidgetWrapper(forms.Widget):
    """
    This class is a wrapper to a given widget to add the add icon for the
    admin interface.
    """
    def __init__(self, widget, rel, admin_site):
        self.is_hidden = widget.is_hidden
        self.needs_multipart_form = widget.needs_multipart_form
        self.attrs = widget.attrs
        self.choices = widget.choices
        self.widget = widget
        self.rel = rel
        # so we can check if the related object is registered with this AdminSite
        self.admin_site = admin_site

    def __deepcopy__(self, memo):
        obj = copy.copy(self)
        obj.widget = copy.deepcopy(self.widget, memo)
        obj.attrs = self.widget.attrs
        memo[id(self)] = obj
        return obj

    def render(self, name, value, *args, **kwargs):
        rel_to = self.rel.to
        related_url = '../../../%s/%s/' % (rel_to._meta.app_label, rel_to._meta.object_name.lower())
        self.widget.choices = self.choices
        output = [self.widget.render(name, value, *args, **kwargs)]
        if rel_to in self.admin_site._registry: # If the related object has an admin interface:
            # TODO: "id_" is hard-coded here. This should instead use the correct
            # API to determine the ID dynamically.
            output.append(u'<a href="%sadd/" class="add-another" id="add_id_%s" onclick="return showAddAnotherPopup(this);"> ' % \
                (related_url, name))
            output.append(u'<img src="%simg/admin/icon_addlink.gif" width="10" height="10" alt="Add Another"/></a>' % settings.ADMIN_MEDIA_PREFIX)
        return mark_safe(u''.join(output))

    def build_attrs(self, extra_attrs=None, **kwargs):
        "Helper function for building an attribute dictionary."
        self.attrs = self.widget.build_attrs(extra_attrs=None, **kwargs)
        return self.attrs

    def value_from_datadict(self, data, files, name):
        return self.widget.value_from_datadict(data, files, name)

    def _has_changed(self, initial, data):
        return self.widget._has_changed(initial, data)

    def id_for_label(self, id_):
        return self.widget.id_for_label(id_)
